Puncturing device for tomography

ABSTRACT

A puncturing device that can be observed by means of tomography, such as MRI, which can be operated simply, safely and reliably. One embodiment of the invention includes a cuboid body containing a needle guide, which extends to a base area of the cuboid body. The base area is configured for placement on the skin of a patient. Marker bores disposed in the cuboid body and containing a contrast medium make it possible to precisely align the needle guide with a tomography picture plane in that the images of the bores have to assume a particular mutual configuration on a monitor. This allows a puncture needle used with the needle guide to be observed along its entire path on tomograms.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to puncturing devices for tomography.

2. Description of the Related Art

Tomography, such as MRI (magnetic resonance imaging), operating in realtime, and CT (computed tomography), is often used in imaging formedicine.

Understood by tomography in connection with the present invention shouldbe imaging methods used in medicine, in particular MRI (magneticresonance imaging), operating in real time, and CT (computedtomography).

Punctures monitored through tomography entail various problems anddifficulties. The spatial relations in the imaging installation are verytight, whereby the dimensions of a puncturing device are limited. DuringMRI, not just any desired materials can be brought into the magneticfield, in particular no ferromagnetic materials. The physician followsthe puncturing needle on the picture screen, and can only see thisneedle as long as it is located at least close to the cutting plane,which is determined in the case of MRI by the magnetic field, and in thecase of CT by the X-rays. Thus it can very well happen that the punctureneedle is visible in the region of the puncture site, but not its point,however, since its point is located in front of, or behind, the pictureplane. It is easy to imagine the difficulties that confront thephysician in such a situation. Upon puncturing of the puncture needle,in particular in the abdominal region of a patient, the tissue can firstbend greatly inward, whereby a sighted organ to be punctured or a tumourcan slip away sideways.

Various devices are known which serve the precise positioning of apatient in a tomographic installation, and which therefore also findapplication in punctures. Several of these devices operate with opticalmeasurement of reference points placed on the body of the patient. Thesereference points can be markings drawn, pasted or also projected on theskin. The last-mentioned can be generated, for example, by means of alaser beam. All these optical devices have in common that they are veryconsuming and therefore expensive. Moreover, their dimensions and theirarrangement in the tomographic installation can impede the physicianduring a puncture, or the physician can disturb the functioning of thepositioning device if he inadvertently interrupts the measuring beams. Asimple and precise way of guiding the needle is not available in any ofthe devices of this kind.

The printed patent specification U.S. Pat No. 4,826,487 relates to analignment button for a stereotaxic plug and method of using the same.The plug can bear a thread on its outer circumference, and is intendedto be placed in the cranium of a patient. It bears a plurality of axialbores disposed in a particular pattern, of which a first group isdesigned as a guide cannulae for surgical instruments. A second group ofaxial bores is designed as marker bores, the bores containing a contrastmedium depending upon the respective tomography. Gold is proposed as thecontrast medium for pictures with X-rays, and for MRI images water orlipids. After insertion of the plug, the scalp is pulled over it andsutured in order to keep the risk of infection as minimal as possible.The alignment button contains cannulae and marker bores disposed in apattern identical to the pattern of the plug. It is precisely alignedwith the plug in a corresponding imaging device, and then sewn to thescalp. With this system both an exact locating of the puncture site bymeans of a tomographic method as well as a precise guiding of a surgicalinstrument, for example a puncture needle, are possible. However, thissystem can only be used sensibly for surgical interventions repeated attemporal intervals, in particular in the skull, and is not suitable forsingle punctures. Indicated in the printed patent specification is thatthe alignment button can also be used alone. The guiding of the needleis thereby omitted, however, so that although the puncture site isdeterminable by means of the alignment button, the direction of punctureof the needle is not.

The printed patent specification U.S. Pat. No. 5,178,146 relates to asystem for aligning a patient for use of MRI or other imaging methods.The system includes in particular a cuboidal box to be placed spacedapart from the region of the body of the patient to be examined, in thewalls of which box tubes, filled with a contrast medium, have beenplaced in a particular pattern. Indicated as contrast medium for MRI is,for example, a gadolinium compound, and for CT, a barium compound. Bothtubes disposed in a right-angle pattern as well as tubes disposedrunning diagonally are provided. The latter generate shadows in thepicture which displace themselves in the picture plane when the box ismoved through the field. From the mutual position of these shadows thephysician can discern whether the patient has assumed the desiredposition in the imaging installation. This system is intended inparticular to bring into line pictures generated by means of MRI withpictures generated by other means. For this purpose the contrast mediumin the tubes is exchangeable. One application example is in radiationtherapy in which, for example, a tumour is first located by means ofMRI, and subsequently irradiated with X-rays. The precise position forirradiation is then reached when the pattern generated by the tubes onthe CT picture coincides with that on the previously generated MRIpicture. Although it is mentioned in the printed patent specificationthat the system can also find application for punctures, there are noindications of a needle guide. Above and beyond that, it is apparentthat the said box can additionally impede the doctor when puncturing.

BRIEF SUMMARY OF THE INVENTION

It is the objective of the present invention to create a puncturingdevice which can be manufactured simply and inexpensively, and can beoperated safely and reliably. Another objective of the invention is toprovide a puncturing device with small dimensions, and which thereforeis usable with the narrow space relations that prevail in the imaginginstallation. A further objective of the invention consists in creatinga puncturing device which can be made of materials that cause nointerference during the respective tomographic procedure. Furthermorethe invention has the objective of providing the physician with apuncturing device with which the puncture needle can be alignedprecisely with the picture plane, so that this needle can be observed atany time on the picture screen from the puncture site to the point.Finally, with the puncturing device according to the invention therespective bodily region of the patient should be able to be compressedbefore insertion of the puncture needle, so that the indentation of thisregion and thereby a slipping away of the organ or tumour to bepunctured can be minimized. These objectives are achieved through thepresent invention.

In some embodiments of the present invention, a puncturing device isprovided that comprises a body with substantially the shape of a cuboidhaving a base area parallel to a longitudinal axis of the body. The basearea is configured to be placed upon the skin of a patient. A guidemeans cuts the base area at a right angle, and there are at least twoelongated hollow spaces disposed at right angles to the longitudinalaxis of the body, but not parallel to the guide means and not parallelto one another.

A further object of the invention consists in proposing a puncturingdevice which can be removed after insertion of the puncture needle intothe body of a patient, without the puncture needle having to be pulledout for this purpose. This object is achieved through a puncturingdevice having the features of claim 7.

Further special embodiments of the puncturing device according to theinvention are described in the dependent claims.

The invention will be described more closely in the following withreference to the embodiments presented in the drawings.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

FIG. 1 is an enlarged elevation view showing an embodiment of thepuncturing device according to the present invention.

FIG. 2 is a top view of the embodiment of the present inventionaccording to FIG. 1.

FIG. 3 is a side elevation view of the embodiment of the presentinvention according to FIG. 1.

FIG. 4A is a perspective view of a correctly aligned puncturing deviceaccording to FIG. 1.

FIG. 4B is a tomogram, represented schematically, of the device alignedaccording to FIG. 4A.

FIG. 5A is a perspective view of a puncturing device according to FIG.1, which is shifted parallel with respect to the picture plane.

FIG. 5B is a tomogram, represented schematically, of the device disposedaccording to FIG. 5A.

FIG. 6A is a perspective view of a puncturing device according to FIG.1, which is disposed in the picture plane rotated about a vertical axis.

FIG. 6B is a tomogram, represented schematically, of the device disposedaccording to FIG. 6A.

FIG. 7A is a perspective view of a puncturing device according to FIG.1, which is disposed in the picture plane rotated about a horizontalaxis.

FIG. 7B is a tomogram, represented schematically, of the device disposedaccording to FIG. 7A.

FIG. 8A is a perspective view of a puncturing device according to FIG.1, which is disposed in the picture plane rotated about a horizontal anda vertical axis.

FIG. 8B is a tomogram, represented schematically, of the device disposedaccording to FIG. 8A.

FIG. 9 is a perspective view of another embodiment of the puncturingdevice according to the present invention, comprising two identicalparts, manufactured by injection moulding, which are in the process ofbeing joined together.

FIG. 10 is the embodiment according to FIG. 9 in completely assembled,ready-to-use state.

FIG. 11 is a tomogram, represented schematically, of the deviceaccording to FIG. 10 with correct alignment.

FIG. 12 is the embodiment according to FIG. 9, after use, in a separatedstate.

FIG. 13 is another embodiment of the puncturing device according to thepresent invention.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1 to 3 show an embodiment of the puncturing device according tothe invention. A cuboid 1 with rounded edges, which comprises syntheticmaterial, forms the main part of the device. A guide bore 2, continuousfrom top to bottom—in the position for use—serves to accept a needleguide 3, which includes a handle 4 and a guide tube 5 firmly connectedthereto. In some embodiments the handle is a synthetic material and theguide tube is titanium. The needle guide 3 in this embodiment can be adisposable part, and the handle 4 can be coloured so that it isdiscernable at first glance which needle diameter the needle guide isconfigured for. As can be seen clearly in FIG. 1, the guide tube extendsto the contact surface 6 of the cuboid 1, which can be placed upon theskin of a patient.

Present in the cuboid are a plurality of marker bores, represented inFIGS. 1 to 3 by broken lines. In the present example they are designedas blind-hole bores, filled with a contrast medium and closed bystoppers 7. Used as contrast medium can be the substances known from thestate of the art used for this purpose. For MRI purposes, the followingmixture has proved to be especially good: lobitridol (or other iodineRKM), gadopentetate dimeglumine, methylhydroxy-ethyl-cellulose andwater. The gadolinium concentrate range should be thereby selected frombetween 0.5 mM and 40 mM, whereby the optimal range lies close to 1 mM.Furthermore practice has shown that during CT, air can also be used asthe contrast medium. In the perpendicular, longitudinal central plane ofthe cuboid, there are marker bores 8 and 9, which, from opposite sides,extend into the vicinity of the needle guide 3. Further marker bores 10to 13 lie in parallel planes, perpendicular to the said perpendicularlongitudinal central plane, and project from the upper edge regionsdiagonally into the interior of the cuboid. Finally, two more markerbores 14 and 15 are provided, conically pointed at their inner-lyingend, which bores, coming from opposite sides, extend parallel, spacedwith respect to one another, and at the same distance from the contactsurface 6, perpendicular up to the longitudinal central plane. The borescrossing one another 10 and 11, respectively 12 and 13, can also cut inpairs.

In the following it will be shown, with reference to the drawing FIGS. 4to 8, how the device described above is used. Assumed is that thephysician wants to puncture an organ in the abdomen of a patient withthe aid of an MRI device. The puncturing device according to theinvention is suitable both for short, closed as well as for open MRIsystems. After the physician has decided upon a needle diameter, forexample 1.2 mm, a corresponding, sterilised cuboid 1 is prepared, whoseguide bore 2 has a diameter of, for example, 1.6 mm. A needle guide 3 istaken from a sterile package, and is inserted into the guide bore 2. Toprevent contamination of the opening of the needle guide, this can besealed, for example with a little rod of synthetic material, which ispulled out on the side of the contact surface 6 after insertion of theneedle guide 3.

After the organ has been located, the puncturing device, that is thecuboid 1 with inserted needle guide 3, is placed with the contactsurface 6 on the abdominal wall of the patient. As soon as the cuboidcomes into the operating range of the MRI, the marker bores arediscernible as shadows on the picture screen. These shadows aredesignated in FIGS. 4B to 8B by the reference symbols of thecorresponding marker bores, respectively of the guide tube, supplementedby a “B”. The puncturing device has attained the correct alignment shownin FIG. 4A, if a picture corresponding to FIG. 4B appears on themonitor. Understood by “correct” in this context is that the needleguide is situated precisely in the picture plane and thus it is ensuredthat, with unchanged position, the puncture needle can be observed onthe monitor along its entire route. It is also to be mentioned here thatin particular with MRI the area represented is actually not a plane, butrather a layer with a thickness of 3 to 6 mm. In FIG. 4B, the littleguide tube 5, made of titanium, of the needle guide 3 <is> to berecognised along its entire length. The marker bores 8 and 9 appear aslines of even width 8B and 9B, and the marker bores 10 to 13 generateoval dots 10B to 13B, all of which are situated on a horizontal straightline. Finally, the marker bores 14 and 15 situated in the vicinity ofthe contact surface 6 are to be recognised as dots of equal size 14B and15B.

Shown in FIGS. 5 to 8 are views which the physician could be given ifthe puncturing device is not exactly aligned with the respect to thepicture screen. FIG. 5B shows a picture of the position illustrated inFIG. 5A in which the device is situated in front of the picture plane.The images of the guide tube 5 and of the marker bore 15 are not presentin this figure because these parts are located in front of the pictureplane. From the narrow, but evenly thick lines 8B and 9B, it can bededuced that the cuboid is oriented parallel to the picture plane. Bothfrom the ovals 10B to 13B, which are not situated on a straight line,but are shifted vertical toward one other, as well as from the absenceof an image of the marker bore 15, one can see that the cuboid has to bepushed away from the observer, so that its middle plane is aligned withthe picture plane. Although the needle guide 3 is located precisely inthe picture plane in FIGS. 6A and 6B, the puncturing device isnevertheless rotated about the axis of the needle guide. This is to berecognised from the irregularly thick lines 8B and 9B, and also from thedots 10B to 13B, not aligned on a straight line, and also from the dots14B and 15B, whose diameter should be smaller. According to FIGS. 7A and7B, the puncturing device is rotated about an axis X parallel to thepicture plane and at a right angle to the needle guide. The dots 10B to13B are nevertheless aligned in a straight line, from which it can beconcluded that the region of the longitudinal middle axis of the cuboidlies in the picture plane; however, it can be clearly seen that not allthese dots have the same shape, which indicates a rotation of the cuboidabout this very longitudinal middle axis. This is to be seen, by theway, also from the fact that only one image 5B of the guide tube 5, ofthe middle region, is visible. Finally the absence of the image of themarker bore 14 indicates that the region of the cuboid near the contactsurface 6 lies behind the picture plane. From this it is alsoimmediately clear to the doctor in which direction the correction musttake place. Finally, FIGS. 8A and 8B show still another position of thepuncturing device, in which the wrong positions shown in FIGS. 6A, 6B,7A and 7B are combined. The position of the dots 10B to 13B indicatesthat the cuboid is further removed from the correct position to the leftthan to the right, it being recognisable from dot 14B that the leftregion apparently lies in front of the picture plane. Consequently thephysician will first rotate the left region of the device in thedirection of the picture plane, after which the picture will appearapproximately as shown in FIG. 7B; from this position then a rotationabout the X axis suffices, whereby the upper region of the device isturned toward the picture plane in order to achieve the picture shown inFIG. 4B and thereby a precise alignment of the device.

As soon as the puncturing device is oriented according to FIGS. 4A and4B, and of course also the site to be punctured is aligned with thepicture plane, the puncture needle is inserted into the needle guide 3.For this purpose the latter has a conically widened opening at its upperend. Before the doctor inserts the puncture needle into the body of thepatient, he compresses the respective bodily region in that he pressesthe puncturing device against the abdominal wall. The risk of a slippingaway of the respective organ during the subsequent penetration of theneedle is thereby considerably reduced. Furthermore by means of thisstep, the entire device comes closer to the organ to be punctured, andcan therefore be aligned therewith even more precisely. Since the guidetube 5 of the needle guide 3 extends to the skin of the patient, thepuncture takes place exactly at the desired place. Thanks to the factthat the puncture direction of the puncture needle is guided preciselyby means of the device according to the invention, the needle's path canbe followed on the monitor and watched closely, and the puncture can becarried out exactly at the desired place.

After the operation, the needle guide 3 is removed from the cuboid 1,and is disposed of. The cuboid is sterilised and made ready for reuse, acold sterilisation method having to be employed when the contrast mediumin the marker bores is fluid.

The second embodiment example shown in a perspectival view in FIG. 9 isintended for one-time use, and consists of two identical parts 21produced from a synthetic material by means of injection moulding. Theseparts 21 are constructed such that they can be joined in the positionshown in FIG. 9 and then form a cuboid, which corresponds to the cuboid1 of FIGS. 1 to 3. When joining the two parts 21, a tab 22 of each partslides into a guide 23 on the other part in each case, until the frontedge of the tab is slightly lifted by means of an activity of a lockingprojection 25. Upon further pushing together of the two identical parts,the locking projection 25 comes into the region of a recess 24 providedin the tab, so that the tab springs back from its raised position andthe locking projection 25 is accepted in the recess 24. This endposition, in which the parts 21 form a body corresponding to the cuboidof FIGS. 1 to 3, is shown in FIG. 10. A recessed grip 27 is provided inthe side faces of the parts 21 for better handling of the cuboid by thephysician.

The cuboid formed by the parts 21 also has marker bores. The marker bore28 corresponds thereby to the marker bores 8 and 9 of the embodimentaccording to FIGS. 1 to 3, the marker bore 29 corresponds to the markerbores 10 and 12 of FIGS. 1 to 3, and the marker bore 30 is, like themarker bores 14 and 15 of FIGS. 1 to 3, conically pointed at itsinner-lying end. The marker bore 31, lying in a horizontal plane,replaces the marker bores 11 and 13 of the embodiment example accordingto FIGS. 1 to 3. The guide bore 32 has a smaller diameter than the guidebore 2 according to FIGS. 1 to 3 because in this embodiment example theneedle guide 3 is done away with, and the puncture needle is thus guideddirectly in the cuboid. For easier insertion of the puncture needle, acountersink 33 is provided on the upper end of the guide bore 32. Thehollow space 34 visible on the left side of FIGS. 9, 10 and 12, isconstruction-related since, as is well known, pieces which aremanufactured by injection moulding must have wall thicknesses which areas regular as possible. This is of no significance for the functioningof the device, however.

FIG. 11 shows schematically, in a way similar to FIG. 4B, a tomogram ofthe device according to FIG. 10 with correct alignment. The marker bores29 running slanted in the cuboid with respect to the supporting surfaceare visible as shadows 29B, which move upward and downward in thepicture when the cuboid is pushed transversely to the picture plane. Themarker bores 31 running parallel to the supporting surface generateshadows 31B on the picture which remain at the same place during amovement of the cuboid transversely to the picture plane. Thus thepuncturing device is aligned exactly in the picture plane when the dots29B and 31B are disposed on the picture along a straight line, the areas28B are visible, and the dots 30B are equally large. So that the dots29B, formed through the bores 29 running slanted, appear round, thebores 29 in this example are designed in the shape of an ellipse, whoselonger axis is disposed parallel to the base area.

As already mentioned, the puncturing device according to FIGS. 9 to 12is conceived for one-time use. For this purpose it is delivered in thestate shown in FIG. 10, packed in a sterile way. As soon as the point ofthe puncture needle has reached its target in the body of the patient,the task of the cuboid is fulfilled. The cuboid can now impede thephysician during further manipulations of the puncture needle, andremoving it, therefore, is desired. For this purpose the cuboid consistsof the two said parts 21, which are separated from one another afteruse. To achieve this, the doctor bends the tabs 22 outward in order tobring out of engagement the recesses 24 and the locking projections 25.A nick 26 is provided on the tab 22, which causes the tab to break offwhen bent outward. A reuse of the no longer sterile device is therebyprevented. FIG. 12 shows the two separated parts with the resultantbreaking area 35 in the region of the nick. The tab 22 and the nick 26are dimensioned such that the tab does not break during assembly of thetwo parts 21. If necessary, for assembly, the parts can be slightlyheated.

Shown in FIG. 13, in perspective and partially cut open, is a further,alternative design of the puncturing device according to the invention.The principle described in the foregoing is reversed here in that thecuboid 41 is designed substantially hollow and is filled with contrastmedium. The guide bore 42 for the puncture needle is located in a guidetube 43 which passes through the hollow cuboid. Connected to both endwalls of the cuboid is one alignment body 44 each, which serves to alignthe device with the picture plane. Each alignment body 44 tapers in thedirection toward the guide bore, so that its lateral peripheries 45 aredesigned elongated and are disposed not parallel to the guide means andnot parallel to one another. In operation, a similar effect therebyresults as with the previously described embodiments. The more thecentral plane of the cuboid, in which the guide bore 42 is located,approaches the picture plane, the longer the shadows formed by thealignment body 44 become, which extend from the end faces of the cuboidin the direction toward the guide bore. In this embodiment further guidebodies can also be provided of course, which aid the precise positioningof the cuboid in the picture plane. These alignment bodies can bedisposed in a way similar to the marker bores of the previouslydescribed embodiment examples, only bores are not involved here, butbodies which extend from the walls of the hollow cuboid into itsinterior.

What is claimed is:
 1. A puncturing device for aligning a punctureneedle with a tomography picture plane, comprising: a body,substantially cuboid in shape, having a base area parallel to alongitudinal axis of the body; a guide means, for the puncture needle,disposed in the body wherein an axis of the guide means cuts the basearea at a right angle; and a plurality of elongated hollow spacescontaining contrast medium disposed in the body, wherein at least two ofthe elongated hollow spaces are at a right angle to the longitudinalaxis of the body, but not parallel to the guide means, and not parallelto one another.
 2. The puncturing device according to claim 1, whereintwo of the elongated hollow spaces are at a right angle to thelongitudinal axis of the body but not parallel to the guide means andnot parallel to one another, and are located on opposite sides of theguide means.
 3. The puncturing device according to claim 1 or 2,wherein: at least one of the elongated hollow spaces extends from an endface of the cuboid body into the vicinity of the guide means, in a planedefined by the longitudinal axis of the body and the axis of the guidemeans; and at least another of the elongated hollow spaces extends fromanother face of the cuboid body into the vicinity of the guide means, inthe plane defined by the longitudinal axis of the body and the axis ofthe guide means.
 4. The puncturing device according to claim 3, wherein:at least one of the elongated hollow spaces extends from a side face ofthe cuboid body into the vicinity of the guide means, at a right angleto the plane defined by the longitudinal axis of the body and the axisof the guide means; and at least another of the elongated hollow spacesextends from another side face of the cuboid body into the vicinity ofthe guide means, at a right angle to the plane defined by thelongitudinal axis of the body and the axis of the guide means.
 5. Thepuncturing device according to claim 1 or 2, wherein: at least one ofthe elongated hollow spaces extends from a side face of the cuboid bodyinto the vicinity of the guide means, at a right angle to a planedefined by the longitudinal axis of the body and the axis of the guidemeans; and at least another of the elongated hollow spaces extends fromanother side face of the cuboid body into the vicinity of the guidemeans, at a right angle to the plane defined by the longitudinal axis ofthe body and the axis of the guide means.
 6. The puncturing deviceaccording to claim 5, wherein: at least one of the elongated hollowspaces extends from an end face of the cuboid body into the vicinity ofthe guide means, in the plane defined by the longitudinal axis of thebody and the axis of the guide means; and at least another of theelongated hollow spaces extends from another end face of the cuboid bodyinto the vicinity of the guide means, in the plane defined by thelongitudinal axis of the body and the axis of the guide means.
 7. Thepuncturing device according to claim 1, wherein the elongated hollowspaces are blind bores whose outer-lying end is closed.
 8. Thepuncturing device according to claim 1, wherein the guide means furthercomprises a guide tube removably inserted in a guide bore, the guidetube having a handle fastened to one end with a conical insertionopening for a puncture needle.
 9. The puncturing device according toclaim 1, wherein the body is separable into at least two parts in theregion of the guide means such that the parts are removable from thepuncture needle without the puncture needle having to be pulled backalong its axis.
 10. The puncturing device according to claim 9, whereinthe separable parts of the body meet in a plane containing the guidemeans.
 11. The puncturing device according to claim 10, wherein theseparable parts of the body are held together by engagement means. 12.The puncturing device according to claim 11, wherein the engagementmeans are resilient tabs having locking projections which secure to theopposing separable part of the body.
 13. The puncturing device accordingto claim 12, wherein the resilient tabs have break-off sites which breakif the resilient tabs are bent for the purpose of releasing the lockingprojections.
 14. The puncturing device according to claim 1 or 9,wherein the guide means comprise a guide boar, an end of the guide boarremote from the base area having a conical extension for easierinsertion of the puncture needle.
 15. A puncturing device for aligning apuncture needle with a tomography picture plane, comprising: a hollowbody, substantially cuboid in shape, having a base area parallel to alongitudinal axis of the body; a guide means for the puncture needle,the guide means being disposed in the body and wherein the axis of theguide means cuts the base area at a right angle; and alignment bodiescomprising contrast medium, disposed in the body, wherein the alignmentbodies have elongated peripheries which are disposed not parallel to theguide means and not parallel to one another.